Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/006—Refining fats or fatty oils by extraction

Definitions

• Fats and oils play an important role in human nutrition and as raw materials for the chemical industry. Further processing into surfactants, plasticizers, lubricants, waxes, fatty alcohols etc. should be mentioned here.
• the main components of fats and oils are the triesters of glycerin and fatty acids, the triglycerides.
• the physical properties of fats and oils are determined on the one hand by the chain length of the fatty acids, on the other hand by the degree of saturation of the fatty acids and also by the distribution of the various fatty acids over the three hydroxyl groups of the glycerol. Fats with a high proportion of saturated fatty acids are generally solid at ambient temperature. Those from predominantly unsaturated fatty acids are liquid at ambient temperature.
• the natural fats and oils contain a number of by-products that affect shelf life, smell, taste and appearance. The most important are suspended matter, organic phosphorus compounds, free fatty acids, coloring and odorants. Phosphatides, mucilages and other complex colloidal compounds can promote hydrolytic degradation during storage and have an adverse effect on further refining. That is why they are removed by so-called degumming. It is based on hydration with water or direct steam. The phosphatides and mucilages absorb water, swell and become insoluble. After finely divided solids and phosphorus compounds have been removed by filtration and degumming, the further task of the preparation is to separate free fatty acids, coloring and odorous substances. This is the subject of the present invention.
• the commercially available raw fats contain on average 1 to 3% free fatty acid, good types 0.5% and less, some palm, olive and fish oils 20% and more.
• the fatty acid content of the refined fats and oils should generally be less than 0.2%. While longer-chain free fatty acids mostly have no flavor Cause impairment, the short-chain have a soapy, rancid taste.
• deacidification is mainly carried out by treatment with alkali or by distillation.
• removal by esterification with glycerol, by selective solvent extraction and adsorbents is of little importance.
• the free fatty acids are continuously removed from the crude oils with steam under vacuum. It is not so important to completely distill off the fatty acids. Rather, the acids remaining in small amounts are expediently removed by post-refining with alkali. Before the deacidification by distillation, however, the crude fat must be freed as completely as possible of mucilage, phosphatides and traces of metal - usually by treatment with phosphoric acid - since the accompanying substances can lead to dark-colored and unpleasant tasting substances during the distillation which can hardly be removed are.
• the neutralization of oils by separating the free fatty acids from the crude fat using selectively acting solvents is primarily suitable for highly acidic oils and fats.
• Ethanol as a solution medium enables, for example, the deacidification of olive oil with 22% free fatty acids by liquid-liquid extraction down to 3% free fatty acids.
• Another extractant that only dissolves free fatty acids and very highly unsaturated triglycerides at suitable temperatures is Furf rol.
• liquid propane is used as an extractant in countercurrent. The liquid propane selectively dissolves saturated neutral oil. Fatty acids, oxidation products, unsaponifiable matter and the highly unsaturated glycerides are hardly dissolved and remain.
• the process is mainly used for the fractionation of fish oils and fish liver oils.
• a decolorization step is generally switched on. It is usually decolorized with solid adsorbents, e.g. Bleaching earth and activated carbon. Air or chemical bleaching plays a minor role in edible fats.
• odors and flavors are removed from the deacidified and bleached oils and fats.
• Deodorization essentially consists of steam distillation, in which the volatile compounds are separated from the non-volatile glycerides.
• the aromas and flavors are predominantly aldehydes and ketones, which are formed by autoxidative or hydrolytic reactions during processing and storage.
• the low partial pressure of the connections to be removed requires implementation damping in a vacuum. Steaming is usually carried out at 180 to 220 ° C and a pressure of 6 to 22 mbar.
• the object of the invention is to provide an economical, environmentally compatible and easy to carry out process for cleaning fats or oils of animal or vegetable origin.
• the process should also enable continuous process management and use substances that are as harmless to health as possible. Impurities such as free fatty acids, flavors, smells and colors should be separated as selectively as possible.
• PEG polyethylene glycols
• the method according to the invention is basically suitable for all fats or oils of animal or vegetable origin.
• the process is particularly suitable for fats or oils having 10 to 22 and preferably 12 to 18 carbon atoms in the fatty acid residue.
• the fat or oil is preferably filtered and degummed.
• the cleaning takes place by extraction with a polyethylene glycol, which is liquid at the extraction temperature.
• a polyethylene glycol which is liquid at the extraction temperature.
• Such polyethylene glycols with an average molecular weight of 200 to 1500 g / mol and in particular 400 to 800 g / mol are generally suitable.
• Polyethylene glycols with a mass weight of 380 to 420 (PEG 400) and a mass weight of 570 to 630 (PEG 600) are particularly suitable.
• Polyethylene glycols in general and in particular the two polyethylene glycols mentioned above are non-toxic and they are approved in pharmacy as matrix material for the administration of active substances.
• Mono- and diethylene glycols are not present in the PEGs available as commercial products. No monoethylene glycol is formed as a metabolite. The toxicity of the products is lower than that of glycerin.
• the hygroscopicity of PEG 600 is one third of the hygroscopic picity of glycerin; that of PEG 400 is about half that of glycerol. Since the mass weight of PEG 600 is greater than that of PEG 400, its vapor pressure is lower. Because of its higher viscosity, extraction with PEG 600 generally requires a higher process temperature than PEG 400. The solubility of triglycerides in PEG decreases with increasing mass weight. As mentioned, in principle all polyethylene glycols with an average molecular weight of 200 to 1500 g / mol are suitable for the deacidification of fats and oils by the process according to the invention. The PEGs should be free of monoethylene glycol and diethylene glycol. Up to the PEG 600, all polyethylene glycols are biodegradable and classified as not hazardous to water. They are therefore particularly suitable for use in the process according to the invention.
• the extraction with the polyethylene glycol is expediently carried out at a temperature between 20 and 200 ° C. and preferably between 50 and 150 ° C.
• working temperatures in the extraction from 100 to 130 ° C. are particularly suitable.
• the carotenes are so readily soluble in PEG that, for example, the extraction of carotenes from palm oil can be carried out in the temperature range from 50 to 150 ° C.
• the regeneration of the loaded polyethylene glycol is not easily possible.
• adding water to the PEG significantly reduces the solubility of PEG in the fatty acids. This can be used to displace the fatty acids from the polyethylene glycol. After adding water, the dissolved fatty acids and odorants can be completely removed from the polyethylene glycol using a suitable extractant.
• Another possibility for regenerating the PEG is stripping with steam at temperatures of preferably 100 to 150 ° C. or stripping the water-containing PEG with carbon dioxide. oxide at elevated temperatures. In the latter case, the stripping process can be used simultaneously to dry the polyethylene glycol.
• the PEG regenerated in this way is expediently returned to the extraction device.
• the process according to the invention can be carried out particularly advantageously as a continuous process in which the extractants used are preferably recovered and reused.
• a fat or oil phase freed from impurities is obtained, which is separated off and washed with water to remove the PEG dissolved therein.
• the fat or oil phase is then preferably dried.
• the aqueous PEG phase can also be separated into its components. For example, distillation or reverse osmosis are suitable.
• the PEG obtained can be used again for extraction.
• Extraction with polyethylene glycol also results in a PEG phase loaded with the impurities extracted from the oil or fat.
• the PEG can be isolated from this and used again for extraction.
• the isolation is advantageously carried out by adding 1 to 10% by weight and preferably 2 to 6% by weight of water to the PEG phase.
• the aqueous PEG phase can be freed from the impurities contained therein by stripping or extraction.
• Low-pressure gases with a reduced temperature at 20 ° C. of greater than about 0.7 can be mentioned as suitable extraction agents. Examples of such low pressure gases are carbon dioxide, propane, butane, dimethyl ether, ethyl acetate and mixtures of at least two of these compounds.
• the extraction is preferably carried out at a pressure which is higher than the vapor pressure of the extracting agent or at a temperature above the critical temperature of the extracting agent and a pressure which is greater than its critical pressure. Suitable extraction temperatures are between 40 and 150 ° C and in particular between 70 and 120 ° C.
• the impurities contained in the PEG are extracted with the extractant.
• the purified PEG can be used again for the extraction.
• the extractant loaded with impurities is preferably separated from the impurities by rectification under reduced pressure and / or elevated temperature. Then it can be used again for the extraction.
• FIG. 1 shows schematically an arrangement for performing the method according to the invention.
• the oil or fat to be deacidified is fed to the extractor A at the bottom and flows through the extraction column from bottom to top in countercurrent to the extracting agent PEG, which has a higher density than the oil.
• the oil phase releases the free fatty acids and odors and flavors to the extractant.
• the PEG pumped in at the top of the extraction column accumulates on the way from top to bottom of free fatty acids and odorants and flavors.
• the oil or fat cleaned of free fatty acids and odorants and flavors leaves the extraction column A at the top and is washed in the countercurrent column B with water in order to remove the PEG dissolved in the raffinate.
• the raffinate purified from the PEG leaves column B at the top and is dried in column E.
• the wash water loaded with PEG, which leaves column B at the bottom, can be prepared by distillation or by reverse osmosis.
• the free fatty acids and by-products dissolved in the PEG are extracted in column C after the addition of about 5 to 10% water at a pressure of about 40 bar in countercurrent with propane or butane or a mixture thereof.
• the purified PEG leaves column C at the bottom and, after decompression to ambient pressure, is returned to extraction column A.
• the dense hydrocarbons loaded with free fatty acids, odors and flavors leave the PEG regeneration column C am Head and are freed from the extracted substances in column D by rectification under a pressure which is lower than the pressure in regeneration column C.
• the solvent-free extract (FFS) is drawn off at the bottom of the rectification column D.
• the hydrocarbons leave the rectification column at the top and are condensed by cooling.
• the liquefied hydrocarbons are pumped back into the PEG regeneration column C.
• the separation factor for the separation of the free fatty acids from the triglycerides is about 7. After the addition of 5% water, the extract phase was extracted with butane, triglycerides, free fatty acids and odor and colorants were removed in this way. After the remaining PEG had dried, the same could be used again for a further extraction.
• the extract After extraction of the extractant, the extract consisted of 59% free fatty acids and 41% triglycerides. The separation factor is about 69. After adding 5% water, the extract phase was extracted with butane. Triglycerides, free fatty acids and dyes were removed from the extractant in this way. After drying the PEG by stripping with air at 180 ° C, the regeneration was complete.
• 500 g of slaughter fat was extracted in a six-stage cross-flow column, each with 500 g of PEG 400 at 60 ° C. and ambient pressure. After a second step the extractant was significantly less colored than after the first step. In the further course, the extractant remained colorless. After each stage, a sample was taken from the raffinate and extract phases and analyzed. The free fatty acid content in the raffinate decreased from the initial value from 1.7% to 0.2% after the sixth stage. The raffinate after the sixth stage was colorless and the unpleasant smell of the starting material was gone. In order to remove PEG 400 dissolved in the raffinate, the end product was mixed intensively with 500 g of water.
• the PEG content was reduced from 4.2 to a residual content of 0.3%. Since the phase separation is slow at 60 ° C and the last fine droplets of the extractant can still be present in the raffinate after 30 minutes, the result can be interpreted as meaning that higher working temperatures should be aimed for.
• the oil phase had the following composition: 2.1% by weight of free fatty acids, 4.4% by weight of PEG 400, 360 ppm of carotene and 93.5% by weight of oil.
• the extractant phase contained: 0.75% by weight of free fatty acids, 1.9% by weight of glycerides, 70 ppm of carotene and 97.4% by weight of PEG 400.
• the extract thus obtained consisted of 71.3% by weight of free fatty acids; 27.4% by weight glycerides and 1.4% by weight carotene.
• the raffinate phase contained 98.2% by weight glycerides; 1.7% by weight of free fatty acids; 0.1 wt% PEG 600 and 404 ppm carotene.
• this raffinate was again mixed with 240 g of PEG 600 at 90 ° C. by stirring for 10 minutes. The phase separation was completed three minutes after stopping the stirring process.
• the extract phase of the second extraction stage had the following composition: 99.0% by weight of PEG 600; 1.0% by weight of free fatty acids; 0.4% by weight glycerides and 79 ppm carotene.
• the extracted material was released by adding 10% by weight of water.
• the way The extract obtained in the second extraction stage contained 62.3% by weight of free fatty acids; 37.0% by weight glycerides and 0.8% by weight carotene.
• an oil with a content of 2.0% by weight of carotene was obtained as the end product of the second stage of cross-flow extraction.
• the second stage raffinate phase consisted of 99.1 wt% glycerides; 0.1% by weight PEG 600; 0.8% by weight of free fatty acids and 324 ppm of carotene.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Microbiology (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Fats And Perfumes (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7806261

Family Applications (1)

Country Status (6)

Families Citing this family (6)

Citations (7)

• 1996
  • 1996-09-19 DE DE1996138459 patent/DE19638459A1/de not_active Withdrawn
• 1997
  • 1997-09-05 IN IN520BO1997 patent/IN188738B/en unknown
  • 1997-09-11 AU AU45548/97A patent/AU4554897A/en not_active Abandoned
  • 1997-09-11 WO PCT/EP1997/004977 patent/WO1998012288A1/de active Application Filing
  • 1997-09-18 ID IDP973220A patent/ID19206A/id unknown
  • 1997-09-19 AR ARP970104315 patent/AR008458A1/es unknown

Patent Citations (7)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events